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Law enforcement agencies across the United Kingdom effectively campaigned to use a face scanning system acknowledged as biased against females, youths, and members of ethnic minority groups, following complaints that a more accurate version generated fewer potential suspects.

The Technology in Practice

British police use the national police database to carry out retrospective facial recognition searches. This procedure entails comparing a reference photograph of a person of interest against a database of more than 19 million mugshots to find potential matches.

Acknowledged Discrimination

The UK interior ministry admitted last week that the system was biased. This acknowledgment came after a study by the government's National Physical Laboratory found it misidentified people of Black and Asian heritage and females at much greater frequency than white men. The Home Office said it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users accept discrimination in ethnicity and gender. Operational ease is a weak argument for disregarding basic freedoms.”

Known Issue

Internal documents reveal that this discriminatory flaw has been recognized for over twelve months. Furthermore, police forces lobbied to reverse an initial decision that was intended to mitigate the problem.

Senior officers were notified of the system's bias in late 2024. The Home Office-commissioned laboratory study concluded the system was had a higher probability to suggest incorrect matches for photos of women, individuals of Black ethnicity, and those aged 40 and under.

A Reversed Decision

In response, the National Police Chiefs’ Council (NPCC) ordered that the confidence threshold required for potential matches be raised to a point where the bias was greatly diminished.

However, this directive was overturned the next month after forces complained that the adjusted system was generating fewer “investigative leads”. NPCC documents show the higher threshold cut the number of queries resulting in possible identifications from over half to a just 14%.

Profound Inequalities

Although the Home Office and NPCC declined to specify what setting is now in operation, the latest independent review found the system could generate incorrect matches for Black women almost 100 times more frequently than for white women at certain settings.

The ministry commented on these results: “The testing found that in a limited set of circumstances the algorithm is more likely to wrongly flag some demographic groups in its match reports.”

Balancing Utility and Fairness

Outlining the impact of the brief increase to the system's confidence threshold, the NPCC documents note: “The change significantly reduces the impact of discrimination across legally safeguarded attributes of race, generation and gender but had a substantially detrimental effect on police efficiency”. The papers further note that police units argued that “a once effective tactic now delivered results of limited benefit”.

Wider Implementation Proposals

Meanwhile, the UK administration has launched a two-and-a-half-month consultation on its plans to expand the use of biometric scanning systems. Policing minister Sarah Jones has labeled the tool as the “biggest breakthrough since DNA matching”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the independent scrutiny and oversight board for the national policing equality strategy, said: “There was scant consideration in equality strategy sessions of the technology deployment even with obvious cross-over with the strategy's goals.

“These revelations demonstrate yet again that the anti-racism commitments policing has undertaken via the equality initiative are failing to be integrated into wider practice. Independent assessments have cautioned that innovative tools are being rolled out in a context where ethnic inequalities, weak scrutiny and faulty information gathering continue to exist.

“All deployment of facial recognition must adhere to strict national standards, be independently scrutinised, and prove it reduces rather than compounds racial disparity.”

Home Office Response

A government representative said: “We treat the findings of the study seriously and we have already taken action. A updated software has been independently tested and procured, which has demonstrated no measurable discrimination. It will be trialled early next year and will be undergo evaluation.

“Our priority is ensuring public safety. This revolutionary tool will assist officers to apprehend and prosecute offenders. There is human involvement in every step of the process and no further action would be pursued without specialist personnel carefully reviewing the output.”